March 13th, 2015
By their response to an earthquake impact, all isolation units may be divided into two basic categories: shear units and sliding units. Saint-Gobain Seals’ polymer materials are used for the latter as an ideal sliding tape due to their very low friction, high resistance to wear and resistance to deformation. When an earthquake occurs and the shaking intensifies, the sliding seismic isolator (a laminated bearing with a sliding mechanism) works to absorb strong tremors. The idea behind base isolation is to detach (isolate) the building from the ground so that earthquake motions are not transmitted up through the building or are greatly reduced.
As an earthquake prone country, Japan has been concentrating on base isolation research and development for almost 20 years; their first large base-isolated building was completed in 1986. Seismic base isolation engineering can be seen on several well-known Japanese structures that use Saint-Gobain’s Rulon® and Fluoroloy® products such as the world’s largest suspension bridge where it protects the cable connection underneath the road from earthquake and wind/wave vibration. One of their most famous baseball stadiums adopted a seismic isolation system with the Rulon® and Fluoroloy® products to its roof over the grandstand, which has a no-pillars structure. These are two examples of larger-use applications; however, the materials have also been successful in the building of important, smaller facilities such as hospitals. The use of Saint-Gobain Seals’ products in seismic base isolation systems is not just limited to commercial structures but also applied in high-end residential buildings (common protection for housing throughout Japan).
As there are over 100 standard Rulon® and Fluoroloy® grades, they have been used worldwide in a variety of markets as they withstand a variety of harsh environments such as extreme dryness, cryogenic temperatures, water, steam and hydrocarbon fuel. Some applications include Rulon® J glide rings that improve the performance of high-end rear shock absorber on bicycles, Rulon® J sliding elements that support the bogie of trains in Washington DC, Rulon® 123 cup seals in metering pumps, bonded Rulon® bearings for jet engine thrust reverser and missile launch systems, and Fluoroloy® seals in chemical analyzers.